The patch titled memory hotplug)allocat: usemap on the section with pgdat has been added to the -mm tree. Its filename is memory-hotplugallocate-usemap-on-the-section-with-pgdat.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: memory hotplug)allocat: usemap on the section with pgdat From: Yasunori Goto <y-goto@xxxxxxxxxxxxxx> Usemaps are allocated on the section which has pgdat by this. Because usemap size is very small, many other sections usemaps are allocated on only one page. If a section has usemap, it can't be removed until removing other sections. This dependency is not desirable for memory removing. Pgdat has similar feature. When a section has pgdat area, it must be the last section for removing on the node. So, if section A has pgdat and section B has usemap for section A, Both sections can't be removed due to dependency each other. To solve this issue, this patch collects usemap on same section with pgdat. If other sections doesn't have any dependency, this section will be able to be removed finally. Signed-off-by: Yasunori Goto <y-goto@xxxxxxxxxxxxxx> Cc: Badari Pulavarty <pbadari@xxxxxxxxxx> Cc: Yinghai Lu <yhlu.kernel@xxxxxxxxx> Cc: Yasunori Goto <y-goto@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/sparse.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff -puN mm/sparse.c~memory-hotplugallocate-usemap-on-the-section-with-pgdat mm/sparse.c --- a/mm/sparse.c~memory-hotplugallocate-usemap-on-the-section-with-pgdat +++ a/mm/sparse.c @@ -239,11 +239,22 @@ static unsigned long *__kmalloc_section_ static unsigned long *__init sparse_early_usemap_alloc(unsigned long pnum) { - unsigned long *usemap; + unsigned long *usemap, section_nr; struct mem_section *ms = __nr_to_section(pnum); int nid = sparse_early_nid(ms); + struct pglist_data *pgdat = NODE_DATA(nid); - usemap = alloc_bootmem_node(NODE_DATA(nid), usemap_size()); + /* + * Usemap's page can't be freed until freeing other sections + * which use it. And, Pgdat has same feature. + * If section A has pgdat and section B has usemap for other + * sections (includes section A), both sections can't be removed, + * because there is the dependency each other. + * To solve above issue, this collects all usemap on the same section + * which has pgdat. + */ + section_nr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT); + usemap = alloc_bootmem_section(usemap_size(), section_nr); if (usemap) return usemap; _ Patches currently in -mm which might be from y-goto@xxxxxxxxxxxxxx are hotplug-memory-remove-generic-__remove_pages-support.patch powerpc-hotplug-memory-notifications-for-ppc.patch powerpc-update-lmb-for-hotplug-memory-add-remove.patch powerpc-provide-walk_memory_resource-for-ppc.patch block-fix-memory-hotplug-and-bouncing-in-block-layer.patch mm-make-mem_map-allocation-continuous-v2.patch mm-fix-alloc_bootmem_core-to-use-fast-searching-for-all-nodes.patch mm-offset-align-in-alloc_bootmem.patch mm-make-reserve_bootmem-can-crossed-the-nodes.patch memory-hotplug-register-section-node-id-to-free.patch memory-hotplug-align-memmap-to-page-size.patch memory-hotplug-make-alloc_bootmem_section.patch memory-hotplugallocate-usemap-on-the-section-with-pgdat.patch memory-hotplug-free-memmaps-allocated-by-bootmem.patch ipc-scale-msgmni-to-the-amount-of-lowmem.patch ipc-scale-msgmni-to-the-number-of-ipc-namespaces.patch ipc-define-the-slab_memory_callback-priority-as-a-constant.patch ipc-recompute-msgmni-on-memory-add--remove.patch ipc-invoke-the-ipcns-notifier-chain-as-a-work-item.patch ipc-recompute-msgmni-on-ipc-namespace-creation-removal.patch ipc-do-not-recompute-msgmni-anymore-if-explicitly-set-by-user.patch ipc-re-enable-msgmni-automatic-recomputing-msgmni-if-set-to-negative.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html